Nitroalkyl sulfites and process for preparing them



Patented May 24, 1949 2,4 71,2? 4 NITROALKYL SULFlTES-AN'D PROCESS'rFOR PREPARING v IE-113M Shirley P. Lingo; Terre Hwuta lndg assignor to Commercial Solvents .Cormoration, Terreilaute, .Ind., a corporation -of Maryland No Drawing. Application July' '29, 1946,- Serial No. 686,947

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This invention relates to 'certa-innitroa'lkyl sulfitesand to a method for preparirrgythem'.

It has been known in'the pastthat various chlorinated compoundsoan be prepared from certain" alcohols by-a method which 'comprises'treat ing, the alcohols with various chlorinating agents, including thionylchloride'(S0012), to replace'the hydroxyl group or groupswithchlorme.

I have now found that nitrohydroxy compounds wherein R is a lower alkyl group. From tris- (hydroxymethyl)nitromethane (the only trihydric alcohol falling within the scope of the generic structural formula given above), at least three products are possible:

In preparing the new ester compounds of my invention, I mix a suitable nitrov hydroxy com pound, as defined above, with thionyl chloride, preferably in the presencexof an indifferent solvent i. e, one. whichdoes not reactwith either the reactants Orr-reaction products; and after the desired reaction has taken place, I separate the product by suitable means, such as crystallization orv distillation at low pressure.

The reaction maybecarried out by preparing a solution of thenitro hydroxy compound in a suitable solvent and adding thionyl chloride slowly to thesolution in a suitable reaction vessel, such as=-a.. glass flask, ,aglass-lined metallic. vessel, or other reaction vessel that .istsuitably resistantto the action of the reactantsland reaction product. The thionyl chloride is-ordinarilyadded in a ratio betweenabout. one-half. and one. and one-half moles. @81211'1016- of nitro hydroxy compound, de-.- pending on. the desiredextent of theesteri'fication. The reaction is exothermic, and beginsordinarily aroundrooin temperature; so it is desirable to provide meansiforcooling thereaction mixture, such as .by an external jacket or liquid bath, or an-,-internal.coil. It isdesirable, also, to agitate thereaction mixturein order to assist the reaction and the rateot heat transfer. After the greater portion of the reaction has taken place, it is desirable to heat the. reaction mixture to a temperature around to C., or somewhat higher, for a period up to around three hours, in order to drive the reaction to completion. The desired nitroalkyl esters maythen be separated by-convention-al means: For-example, a'portion of the solvent may be removed by distillation, and the desiredproduct maybe crystallized from the resulting concentrate, or from a solution of the con-centratein anothersolvent, such as acetone.

Amongl the nitro h-ydroxy-= compounds suitable for use' in my process are 2-nitro-2-methy1-1,3- propanedib-l; tri's (hydroxymeth'yl) -nitromethane, Z nitro-LetHyI LB-propanediol, Z-nitro-Z-hexyl- 1J3 propanedi'o'l; 2' nitro-2-isobutyl-1,3-propanediol; and the like.

In preparing the prod-ucts of my invention, it isnecessary to use-"a solvent in the esterification of 'onl'y'th'ose" compounds which are solid at the low temperature-desired; Itispermissible to use a; solvent in all cases, however, in order to assist in' heattransfer, and inorder to minimize any tendency of 'the'thionylchloride to produce overesterifi'tiation at the point where it enters the reaction mixture: Any solvent, in general, which does -not react with 'nitro hydroxy compounds; thionyl chloride; or-nitroalk'yl sulfites is suitable for use in my processz As 'examples of such sol vents may be mentioned carbon tetrachloride; methylenechloride; chloroform; and the like.

The iollowingspecific-examples will further'il' lustrate my invention:

total yield of 2-nitro-2-methyl-1,3-propanedio1' sulfite was nearly the theoretical amount. After recrystallization from alcohol, the product melted at 110 to 112 C.

Example II A round-bottom, three-neck reaction flask was equipped with a stirrer, a dropping funnel, a reflux condenser, and a thermometer. In it, a suspension of 101 grams (0.66 mole) of tris(hydroxymsthybnitromethane in 210 ml. of d y Carbon tetrachloride was heated to reflux (liquid temperature 65 to 75 C.), and 119 grams (1.0 mole) of thionyl chloride were added fairly rapidly. Much gas was evolved, and the mixture darkened in color. Refiuxing was continued for one hour after all of the thionyl chloride had been introduced. Then 200 ml. of water were added at a temperature below 30 C., with the result that a gummy, semisolid mass separated. The water and carbon tetrachloride were decanted, and the residual gum was boiled with methanol. It crystallized readily, giving 71.5 grams of crude product. The conversion to the tris(hydroxymethyl)nitromethane sulfite wherein all of the hydroxyl groups have been esterified was 48.5% of theoretical, based on the nitro triol. On recrystallization from methanol, the product analyzed as follows: Calculated for CsH12O13N2S3, 21.8% S; found, 21.5% S.

Example III A suspension of 151 grams (1.0 mole) of tris- (hydroxymethyl)nitromethane in 400 ml. of carbon tetrachloride was heated to reflux, and to it were added 199 grams (1.0 mole) of thionyl chloride. The mixture Was refluxed an additional thirty minutes, and was then treated with 200 ml. of water. Three layers resulted: a lower layer of carbon tetrachloride, an upper aqueous layer, and a dark, tarry middle layer which proved to contain the product. The latter was heated to 80 C. under high vacuum in an effort to distill it, but without result; and on cooling, it soldified. The solid was dissolved in acetone and treated with an active carbon in an effort to decolorize it; but part of the color remained. When the acetone was evaporated, the residual syrupy liquid crystallized on cooling. Analysis: calculated for the tris (hydroxymethyl) nitromethane sulfite wherein only one hydroxyl group has been esterified (CrHqOsNS) 16.24% s; molecular weight 197;

found, 15.50% S, molecular weight 203.

The products of my invention are useful in numerous organic syntheses, and in particular as intermediates for the production of amines.

They are also interesting and useful because of the presence. in a single molecule, of both reducing and oxidizing groups.

While the foregoing describes the preferred embodiments of my invention, it will be understood that departures may be made therefrom within the scope of the description and claims. In general, it may be said that any modifications or equivalents that would ordinarily occur to those skilled in the art are to be considered as lying within the scope of my invention.

In accordance with the foregoing specification, I claim as my invention:

1. A process for preparing 2-nitro-2-methyl- 1,3-propanediol sulfite which comprises preparing a mixture of 2-nitro-2-methyl-1,3-propanediol with chloroform, slowly adding thionyl chloride thereto in approximately equimolecular ratio, refluxing the resulting mixture at atmospheric pressure until the reaction is substantially complete, and separating the resulting 2-nitro-2-methyl- 1,3-propanediol sulfite by crystallization.

2. A process for preparing sulfites of tris(hydroxymethyDnitromethane which comprises preparing a mixture of tris(hydroxymethyl)nitromethane with chloroform, slowly adding thionyl chloride thereto in a ratio between about 0.5 and 1.5 moles per mole of tris(hydroxymethyl)nitromethane, refluxing the resulting mixture at atmospheric pressure until the reaction is substantially complete, and separating the resulting sulfites of tris(hydroxymethyl)nitromethane by crystallization.

3. As new compositions of matter, sulphite esters selected from the group consisting of:

and

wherein R is a lower alkyl group.

4. 2-nitro- 2 methyl 1,3 propanediol sulfite having the structural formula:

5. In the production of sulfite esters of nitrohydroxy compounds, the process which comprises preparing a mixture with an inert solvent of a nitro-hydroxy compound having the formula:

(References on following page) 5 6 REFERENCES CITED FOREIGN PATENTS The following references are of record in the Number Country Date file of this patent: 487,253 Germany Dec. 12, 1929 OTHER REFERENCES Kyrides, J. Am. Chem. $00., 66, 1006-7 (1944).

UNITED STATES PATENTS Number Name Date 2,377,148 Hechenbleikner May 29, 1945 

